In an electric test (hereinafter referred to as the wafer test) in a wafer test process for semiconductor integrated circuits, a probe card having a probe needle, which is made of a tungsten base material fabricated to have a needle shape with a diameter of, for example, 200 to 300 μm, is used. And the probe needle of the probe card is contacted to the electrode of the semiconductor integrated circuit to perform the wafer test. The probe needle mainly consisting of the tungsten base material is used, and doped tungsten containing aluminum, potassium, silicon or the like, or rhenium-tungsten containing about 3% by mass of rhenium having high strength and high hardness is generally used.
But, when the above-described probe needle consisting of the tungsten base material is repeatedly contacted to the electrodes in the wafer test, the electrode material such as Al or Al—Cu adheres to its tip, and it finally becomes impossible to perform the normal wafer test. Specifically, a small current is passed when the probe needle is contacted to the electrodes in the wafer test, but an electric current density becomes large because the tip of the probe needle has a small diameter, and the tip of the probe needle has a temperature region to melt the electrode material. And, the melted electrode material adheres to the probe needle and it is oxidized to increase the contact resistance, making the normal wafer test difficult.
Therefore, it is general to remove the electrode material adhered to the tip of the probe needle by polishing so as to reduce the contact resistance, and the probe needle is reused for the wafer test. Since the above method cannot fully remove the electrode material which has entered between tungsten crystals and the electrode material tends to adhere in the early stage, it is determined to use the probe needle made of a tungsten alloy containing, for example, 0.1 to 1.0% by mass of a metal selected from Y, La and Ce or its oxide (for example, see Patent Reference 1).    Patent Reference 1: JP-A 2003-023050 (KOKAI)